Thèses : « Litium ion batteries »

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Smaldone, Antonella. « Phisical chemistry of plasmas and applications to cultural heritage and material science ». Doctoral thesis, Universita degli studi di Salerno, 2018. http://hdl.handle.net/10556/3115.

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2016 - 2017
In this project, the attention has been focused on the laser ablation process and on laser induced plasmas spectroscopic study for two different technological applications. First of all, the analytical LIBS (Lase Induced Breakdown Spectroscopy) technique, which allows to obtain qualitative and quantitative information on the elemental composition of the materias analyzed, has been used and developed. The LIBS has been applied to the study of bronze and silver archaelogical findings, coming from three different sites in Basilicata and dated VI century B.C.. The inverse Calibration Free method, that is new a method, that is new a method of quantitative analysis, has been optimized. … [edited by Author]
XXX ciclo

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Rohde, Michael [Verfasser], et Ingo [Akademischer Betreuer] Krossing. « New conducting salts for rechargeable lithium-ion batteries = Neue Leitsalze für wiederaufladbare Lithium-Ionen Batterien ». Freiburg : Universität, 2014. http://d-nb.info/1123481490/34.

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Björkman, Carl Johan. « Detection of lithium plating in lithium-ion batteries ». Thesis, KTH, Kemiteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-266369.

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With an increasing demand for sustainable transport solutions, there is a demand for electrified vehicles. One way to store energy on board an electrified vehicle is to use a lithium-ion battery (LIB). This battery technology has many advantages, such as being rechargeable and enabling reasonably high power output and capacity. To ensure reliable operation of LIB:s, the battery management system (BMS) must be designed with regards to the electrochemical dynamics of the battery. However, since the battery ages over time, the dynamics changes as well. It is possible to predict ageing, but some ageing mechanisms can occur randomly, e.g. due to variations of circumstances during manufacturing, and variations of battery user choices. Hence, by monitoring ageing mechanisms in situ, the BMS can adapt accordingly, similar to a closed loop control system. One ageing mechanism in LIB:s is lithium plating. This mechanism signifies when Li ions are electrochemically deposited as metal onto the negative electrode of the LIB during charging, and can induce other ageing mechanisms, such as gassing or electrolyte reduction. The present project has investigated a method for detecting Li plating in situ after its occurrence by both analysing the voltage change over time during open-circuit voltage (OCV) periods after charging and monitoring battery swelling forces. Results show a correlation between a high probability of Li plating and the appearance of a swelling force peak and an OCV plateau. However, results also show a possible correlation between the onset of Li plating and the onset of the swelling force peak, while also showing a greater detectability of the force signal compared to the electrochemical signal. Furthermore, the present results show that the magnitudes of both signals are probably related to the amount of plated Li. The amount of irreversibly lost Li from plating is shown to have a possible correlation with accumulation of swelling pressure. However, to further validate the feasibility of these two signals, more advanced analysis is required, which was not available during this project.
Med en ökande efterfråga på hållbara transportlösningar så finns det ett behov av elektrifierade fordon. Ett sätt att lagra energi ombord ett elektrifierat fordon är att använda et litium-jon-batteri. Denna batteriteknologi har många fördelar: t.ex. är dessa batterier återladdningsbara, och de kan leverera höga uteffekter samtidigt som de kan ha ett stort energiinnehåll. för att säkerställa en säker drift av litium-jon-batterier måste batteriets styrsystem vara designat med hänsyn till den elektrokemiska dynamiken inuti batteriet. Dock åldras batteriet med tiden, vilket innebär att denna dynamik ändras med tiden, vilket innebär att styrningen av batteriet måste anpassa sig till denna föråldring. Det är möjligt att förutspå åldring av batterier, men vissa åldringsmekanismer kan ske slumpartat, t.ex. via slumpmässiga förändringar i tillverkningsprocessen av batteriet, eller variationer i användningen av batteriet. Genom att därmed bevaka dessa åldringsmekanismer in situ så kan styrsystemets algoritm anpassa sig utmed batteriåldringen, trots dessa slumpartade effekter. En åldringmekanism hos litium-jon-batterier är s.k. litiumplätering. Denna mekanism innebär att litium-joner elektrokemiskt pläteras i form av metalliskt litium på ytan av litium-jon-batteriets negativa elektrod. Mekanismen kan också inducera andra åldringsmekanismer, t.ex. gasutveckling eller elektrolytreduktion. Detta projekt har undersökt en metod för att detektera litiumplätering in situ efter att plätering har skett, genom att både analysera öppencellspänningens (OCV) förändring med tiden direkt efter uppladdning samt analysera de svällande krafterna som uppstår under uppladdning av batteriet. Resultaten visar på en korrelation mellan en hög sannolikhet för litiumplätering och observationen av en topp i svällningskraft och en platå i OCV-kurvan. resultaten visar också en möjlig korrelation mellan påbörjandet av litium-plätering och påbörjandet av toppen i svällningskraft. Vidare visar även resultaten ett troligt samband mellan signalernas magnitud och mängden pläterat litium. Slutligen visar resultaten också ett möjligt samband mellan irreversibelt pläterat litium och ett svällningstryck som ackumuleras med varje uppladdningscykel. Dock krävs det en validering med mer avancerade analysmetoder för att säkerställa användningsbarheten av dessa två signaler, vilket ej var möjligt inom detta projekt.

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Adelhelm, Philipp. « From Lithium-Ion to Sodium-Ion Batteries ». Diffusion fundamentals 21 (2014) 5, S.1, 2014. https://ul.qucosa.de/id/qucosa%3A32397.

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Herstedt, Marie. « Towards Safer Lithium-Ion Batteries ». Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3542.

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Xu, Chao. « All silicon lithium-ion batteries ». Licentiate thesis, Uppsala universitet, Strukturkemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-261626.

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Lithium-ion batteries have been widely used as power supplies for portable electronic devices due to their higher gravimetric and volumetric energy densities compared to other electrochemical energy storage technologies, such as lead-acid, Ni-Cd and Ni-MH batteries. Developing a novel battery chemistry, ‘‘all silicon lithium-ion batteries’’, using lithium iron silicate as the cathode and silicon as the anode, is the primary aim of this Ph.D project. This licentiate thesis is focused on improving the performance of the silicon anode via optimization of electrolyte composition and electrode formulation. Fluoroethylene carbonate (FEC) was investigated as an electrolyte additive for silicon composite electrodes, and both the capacity retention as well as coulombic efficiency were significantly improved by introducing 10 wt% FEC into the LP40 electrolyte. This is due to the formation of a stable SEI, which mainly consisted of FEC decomposition products of LiF, -CHFOCO2-, etc. The chemical composition of the SEI was identified by synchrotron radiation based photoelectron spectroscopy. This conformal SEI prevented formation of large amounts of cracks and continues electrolyte decomposition on the silicon electrode. An alternative lithium salt, lithium 4,5-dicyano-2-trifluoromethanoimidazole (LiTDI), was studied with the silicon electrode in this thesis. The SEI formation led to a rather low 1st cycle coulombic efficiency of 44.4%, and the SEI layer was found to contain hydrocarbon, ether-type and carbonate-type species. Different to conventional composite silicon electrodes, which require heavy and expensive copper current collector, a flexible silicon electrode, consisted of only silicon nanopowder, Cladophora nanocellulose and carbon nanotube, was facilely prepared via vacuum filtration. The electrode showed good mechanical, long-term cycling as well as rate capability performance.

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Chinyama, Luzendu Gabriel. « Recovery of Lithium from Spent Lithium Ion Batteries ». Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-59866.

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Batteries have found wide use in many household and industrial applications and since the 1990s, they have continued to rapidly shape the economy and social landscape of humans. Lithium ion batteries, a type of rechargeable batteries, have experienced a leap-frog development at technology and market share due to their prominent performance and environmental advantages and therefore, different forecasts have been made on the future trend for the lithium ion batteries in-terms of their use. The steady growth of energy demand for consumer electronics (CE) and electric vehicles (EV) have resulted in the increase of battery consumption and the electric vehicle (EV) market is the most promising market as it will consume a large amount of the lithium ion batteries and research in this area has reached advanced stages. This will consequently be resulting in an increase of metal-containing hazardous waste. Thus, to help prevent environmental and raw materials consumption, the recycling and recovery of the major valuable components of the spent lithium ion batteries appears to be beneficial. In this thesis, it was attempted to recover lithium from a synthetic slag produced using pyrometallurgy processing and later treated using hydrometallurgy. The entire work was done in the laboratory to mimic a base metal smelting slag. The samples used were smelted in a Tamman furnace under inert atmosphere until 1250oC was reached and then maintained at this temperature for two hours. The furnace was then switched off to cool for four hours and the temperature gradient during cooling was from 1250oC to 50oC. Lime was added as one of the sample materials to change the properties of the slag and eventually ease the possibility of selectively leaching lithium from the slag. It was observed after smelting that the slag samples had a colour ranging from dark grey to whitish grey among the samples.The X - ray diffractions done on the slag samples revealed that the main phases identified included fayalite (Fe2SiO4), magnetite (Fe3O4), ferrobustamine (CaFeO6Si2), Kilchoanite (Ca3Si2O7), iron oxide (Fe0.974O) and quartz (SiO2). The addition of lime created new compound in the slag with the calcium replacing the iron. The new phases formed included hedenbergite (Ca0.5Fe1.5Si2O6), ferrobustamine (CaFeO6Si2), Kilchoanite (Ca3Si2O7) while the addition of lithium carbonate created lithium iron (II) silicate (FeLi2O4Si) and dilithium iron silicate (FeLi2O4Si) phases.The Scanning Electron Microscopy (SEM) micrographs of the slag consisted mainly of Fe, Si and O while the Ca was minor. Elemental compositions obtained after analysis was used to identify the different phases in all the slag samples. The main phases identified were the same as those identified by the XRD analysis above except no phase with lithium was identified. No lithium was detected by SEM due to the design of the equipment as it uses beryllium planchets which prevent the detection of lithium.Leaching experiments were done on three slag samples (4, 5 and 6) that had lithium carbonate additions. Leaching was done for four hours using water, 1 molar HCl and 1 molar H2SO4 as leaching reagents at room temperature. Mixing was done using a magnetic stirrer. The recoveries obtained after leaching with water gave a lithium recovery of 0.4%. Leaching with HCl gave a recovery of 8.3% while a recovery of 9.4% was obtained after leaching with H2SO4.It can be concluded that the percentage of lithium recovered in this study was very low and therefore it would not be economically feasible. It can also be said that the recovery of lithium from the slag system studied in this work is very difficult because of the low recoveries obtained. It is recommended that test works be done on spent lithium ion batteries so as to get a better understanding of the possibilities of lithium recovery as spent lithium ion batteries contain other compounds unlike the ones investigated in this study.

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Burch, Damian. « Intercalation dynamics in lithium-ion batteries ». Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54233.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mathematics, 2009.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 153-160).
A new continuum model has been proposed by Singh, Ceder, and Bazant for the ion intercalation dynamics in a single crystal of rechargeable-battery electrode materials. It is based on the Cahn-Hilliard equation coupled to reaction rate laws as boundary conditions to handle the transfer of ions between the crystal and the electrolyte. In this thesis, I carefully derive a second set of boundary conditions--necessary to close the original PDE system--via a variational analysis of the free energy functional; I include a thermodynamically-consistent treatment of the reaction rates; I develop a semi-discrete finite volume method for numerical simulations; and I include a careful asymptotic treatment of the dynamical regimes found in different limits of the governing equations. Further, I will present several new findings relevant to batteries: Defect Interactions: When applied to strongly phase-separating, highly anisotropic materials such as LiFePO4, this model predicts phase-transformation waves between the lithiated and unlithiated portions of a crystal. This work extends the analysis of the wave dynamics, and describes a new mechanism for current capacity fade through the interactions of these waves with defects in the particle. Size-Dependent Spinodal and Miscibility Gaps: This work demonstrates that the model is powerful enough to predict that the spinodal and miscibility gaps shrink as the particle size decreases. It is also shown that boundary reactions are another general mechanism for the suppression of phase separation.
(cont.) Multi-Particle Interactions: This work presents the results of parallel simulations of several nearby crystals linked together via common parameters in the boundary conditions. The results demonstrate the so-called "mosaic effect": the particles tend to fill one at a time, so much so that the particle being filled actually draws lithium out of the other ones. Moreover, it is shown that the smaller particles tend to phase separate first, a phenomenon seen in experiments but difficult to explain with any other theoretical model.
by Damian Burch.
Ph.D.

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Ranom, Rahifa. « Mathematical modelling of lithium ion batteries ». Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/375538/.

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Nazari, Ashkan. « HEAT GENERATION IN LITHIUM-ION BATTERIES ». University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1469445487.

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Barrett, Lawrence Kent. « Silicon Carbon Nanotube Lithium Ion Batteries ». BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/6172.

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Silicon has the highest theoretical capacity of any known anode material, and silicon coated carbon nanotubes (Si-CNTs) have shown promise of dramatically increasing battery capacity. However, capacity fading with cycling and low rate capability prevent widespread use. Here, three studies on differing aspects of these batteries are presented. Here, three studies on differing aspects of these batteries are presented. The first examines the rate capability of these batteries. It compares the cycling of electrodes hundreds of microns thick with and without ten micron access holes to facilitate diffusion. The holes do not improve rate capability, but thinner coatings of silicon do improve rate capability, indicating that the limiting mechanism is the diffusion through the nanoscale bulk silicon. The second attempts to enable stable cycling of anodes heavily loaded with silicon, using a novel monolithic scaffolding formed by coating vertically aligned carbon nanotubes (VACNTs) with nanocrystalline carbon. The structure was only able to stabilize the cycling at loadings of carbon greater than 60% of the electrode by volume. These electrodes have volume capacities of ~1000 mAhr/ml and retained over 725 mAhr/ml by cycle 100. The third studies the use of an encapsulation method to stabilize the solid electrolyte interphase (SEI) and exclude the electrolyte. The method was only able to stabilize cycling at loadings below 5% silicon, but exhibits specific capacities as high as 3000 mAhr/g of silicon after 20 cycles.

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Zhu, Juner. « Mechanical failure of lithium-ion batteries ». Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122143.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 223-244).
The commercialization of lithium-ion batteries has accelerated the electrification process of vehicles. In the past decade, one could see great advances in the life span, cost, performance, specific energy, and specific power of batteries. At the same time, the safety of batteries has not been adequately addressed by most stakeholders in the Electric Vehicle market. The present thesis systematically investigates the deformation mechanisms of the multi-layered structure of lithium-ion battery cells subjected to various loading conditions with particular emphasis on predicting the onset of the electrical short circuit. It starts with a comprehensive testing and modeling study of all the components of the cell, including the current collectors, the separator, the pouch/shell casing, and particularly, the coatings of electrodes.
A detailed computational model for quasi-static loading is subsequently established in Abaqus/explicit, which is very effective to predict the load-displacement response, peak load, displacement to fracture and short circuit, as well as the shear fracture phenomenon. The computational model is then extended to cover the effect of strain rate dependence by introducing the poro-mechanical theory. Darcy's law is used to describe the flow of the electrolyte inside the granular structure of the coating, and the Kozeny-Carman equation is adapted to calculate the permeability of the porous media of the battery cell. The model is shown to accurately predict the strengthening effect of the battery cell under low-speed dynamic loading, observed in experiments. The effect of mechanical deformations of a battery cell on its electrochemical performance is investigated next through a series of control tests on the coin-cell type batteries made of deformed electrodes.
The batteries are tested with ten cycles of charge-discharge, and a clear capacity fade in the damaged cells compared with the undamaged ones is observed. Electrochemical impedance spectroscopy tests are then performed, and the possible mechanism of the capacity fade is proposed. In the last part of the thesis, two applications of the developed computational modeling strategy are exhibited. One is the axial deformation of the 18650 cylindrical cells, and the other is the protective structural design of EV battery pack subjected to a "ground impact".
by Juner Zhu.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Mechanical Engineering

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El, Baradai Oussama. « Elaboration of flexible lithium - ion electrodes by printing process ». Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI036/document.

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Le travail présenté dans ce mémoire concerne la réalisation des batteries souples lithium-ion. Il a comme objectif le développement de nouveaux procédés comme l'impression par sérigraphie pour la fabrication de batteries et le remplacement des polymères issus de la chimie de synthèse par des matériaux bio-sourcés utilisables en milieu aqueux. Les résultats obtenus ont montré qu'il est possible de formuler des encres aqueuses à base des matériaux actifs classiquement utilisés pour l'élaboration d'électrodes (anode et cathode) de batterie Li-ion mais avec des liants dérivés de cellulose en substitution du PVDF qui intègre les formulations standards. Cette encre, dont les propriétés rhéologiques sont compatibles avec le procédé d'impression sérigraphique, permet l'obtention d'électrodes présentant des propriétés spécifiques aux bons fonctionnements de la batterie. Les résultats obtenus ont montré que cette technique d'impression du séparateur pouvait être utilisée pour remplacer la technique de déposition classique des matières actives sur les collecteurs de courant, basée sur un procédé d'enduction à lame (blade coating). Enfin, une batterie lithium-ion imprimée a pu être élaborée en utilisant la stratégie d'impression recto/verso du séparateur avec l'intégration des collecteurs de courant pendant la phase d'impression, validant ainsi cette nouvelle technique d'assemblage
The work presented in this manuscript describes the manufacturing of lithium-ion batteries on papers substrates by printing technique. Its aim is the development of new up scalable and large area techniques as screen printing for the fabrication of lithium-ion batteries and the replacement of conventional toxic components by bio-sourced one and water based solvent. First results shows how it is possible to formulate cellulose based ink tailored for screen printing technology with suitable properties for lithium-ion batteries requirements. Electrodes were manufactured and tested from a physical and electrochemical point of view and two strategies were proposed to enhance performances. Finally, by considering results obtained for the electrodes, a full cell was manufactured with a new assembling strategy based on: front / reverse printing approach and the embedding of the current collectors during printing stage. As a final point cells were characterized and compared with others obtained by conventional assembling strategies

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Popovic, Jelena. « Novel lithium iron phosphate materials for lithium-ion batteries ». Phd thesis, Universität Potsdam, 2011. http://opus.kobv.de/ubp/volltexte/2011/5459/.

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Conventional energy sources are diminishing and non-renewable, take million years to form and cause environmental degradation. In the 21st century, we have to aim at achieving sustainable, environmentally friendly and cheap energy supply by employing renewable energy technologies associated with portable energy storage devices. Lithium-ion batteries can repeatedly generate clean energy from stored materials and convert reversely electric into chemical energy. The performance of lithium-ion batteries depends intimately on the properties of their materials. Presently used battery electrodes are expensive to be produced; they offer limited energy storage possibility and are unsafe to be used in larger dimensions restraining the diversity of application, especially in hybrid electric vehicles (HEVs) and electric vehicles (EVs). This thesis presents a major progress in the development of LiFePO4 as a cathode material for lithium-ion batteries. Using simple procedure, a completely novel morphology has been synthesized (mesocrystals of LiFePO4) and excellent electrochemical behavior was recorded (nanostructured LiFePO4). The newly developed reactions for synthesis of LiFePO4 are single-step processes and are taking place in an autoclave at significantly lower temperature (200 deg. C) compared to the conventional solid-state method (multi-step and up to 800 deg. C). The use of inexpensive environmentally benign precursors offers a green manufacturing approach for a large scale production. These newly developed experimental procedures can also be extended to other phospho-olivine materials, such as LiCoPO4 and LiMnPO4. The material with the best electrochemical behavior (nanostructured LiFePO4 with carbon coating) was able to delive a stable 94% of the theoretically known capacity.
Konventionelle Energiequellen sind weder nachwachsend und daher nachhaltig nutzbar, noch weiterhin langfristig verfügbar. Sie benötigen Millionen von Jahren um gebildet zu werden und verursachen in ihrer Nutzung negative Umwelteinflüsse wie starke Treibhausgasemissionen. Im 21sten Jahrhundert ist es unser Ziel nachhaltige und umweltfreundliche, sowie möglichst preisgünstige Energiequellen zu erschließen und nutzen. Neuartige Technologien assoziiert mit transportablen Energiespeichersystemen spielen dabei in unserer mobilen Welt eine große Rolle. Li-Ionen Batterien sind in der Lage wiederholt Energie aus entsprechenden Prozessen nutzbar zu machen, indem sie reversibel chemische in elektrische Energie umwandeln. Die Leistung von Li-Ionen Batterien hängen sehr stark von den verwendeten Funktionsmaterialien ab. Aktuell verwendete Elektrodenmaterialien haben hohe Produktionskosten, verfügen über limitierte Energiespeichekapazitäten und sind teilweise gefährlich in der Nutzung für größere Bauteile. Dies beschränkt die Anwendungsmöglichkeiten der Technologie insbesondere im Gebiet der hybriden Fahrzeugantriebe. Die vorliegende Dissertation beschreibt bedeutende Fortschritte in der Entwicklung von LiFePO4 als Kathodenmaterial für Li-Ionen Batterien. Mithilfe einfacher Syntheseprozeduren konnten eine vollkommen neue Morphologie (mesokristallines LiFePo4) sowie ein nanostrukturiertes Material mit exzellenten elektrochemischen Eigenschaften hergestellt werden. Die neu entwickelten Verfahren zur Synthese von LiFePo4 sind einschrittig und bei signifikant niedrigeren Temperaturen im Vergleich zu konventionellen Methoden. Die Verwendung von preisgünstigen und umweltfreundlichen Ausgangsstoffen stellt einen grünen Herstellungsweg für die large scale Synthese dar. Mittels des neuen Synthesekonzepts konnte meso- und nanostrukturiertes LiFe PO4 generiert werden. Die Methode ist allerdings auch auf andere phospho-olivin Materialien (LiCoPO4, LiMnPO4) anwendbar. Batterietests der besten Materialien (nanostrukturiertes LiFePO4 mit Kohlenstoffnanobeschichtung) ergeben eine mögliche Energiespeicherung von 94%.

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Jouhara, Alia. « De la conception de matériaux d'électrode organiques innovants à leur intégration en batteries "tout organique" ». Thesis, Nantes, 2018. http://www.theses.fr/2018NANT4026/document.

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Répondre aux besoins croissants en termes de stockage électrochimique sans épuiser les ressources naturelles exige de promouvoir des technologies de batteries en rupture à la fois efficientes mais aussi à faible impact au plan environnemental. La conception de batteries organiques pourrait s'avérer être une partie de la solution. En effet, la richesse de la chimie organique offre une multitude de possibilités pour développer des matériaux d'électrode innovants à partir d’éléments abondants et peu coûteux. Près de 40 ans après la découverte des polymères conducteurs, des batteries Li-organiques offrent maintenant d’intéressantes performances en cyclage. Pourtant, la synthèse de matériaux organiques lithiés électroactifs à haut-potentiel ainsi que celle de matériaux organiques de type p électroactifs à bas potentiel se sont avérées assez complexes et par conséquent, très peu d'exemples de cellules « tout organique » existent. Au cours de ce travail de recherche, nous avons mis en lumière une approche chimique originale consistant à perturber la structure électronique de l’entité organique électroactive (modulation des effets inductifs) au moyen d’un cation spectateur faiblement électropositif ce qui conduit à une augmentation significative du potentiel redox des matériaux d'électrodes organiques lithiés déjà connus. Cette découverte nous a permis de développer une batterie Li-ion « tout organique » capable d’offrir une tension de sortie d’au moins 2,5 V sur plus de 300 cycles. Ensuite, nous avons cherché à concevoir des matériaux de type p capables de fonctionner à bas potentiel et ainsi élaboré des batteries Anion-ion « tout organique ». Enfin, une étude préliminaire d’une nouvelle famille de composés potentiellement bipolaires au plan redox (intégration de centres redox de type n et de type p) a également été réalisée
Meeting the ever-growing demand for electrical storage devices, without depleting natural resources, requires both superior and “greener” battery technologies. Developing organic batteries could well provide part of the solution since the richness of organic chemistry affords us a multitude of avenues for uncovering innovative electrode materials based on abundant, low-cost chemical elements. Nearly 40 years after the discovery of conductive polymers, long cycling stability in Li-organic batteries has now been achieved. However, the synthesis of high-voltage lithiated organic cathode materials and the synthesis of low-voltage p type organic anode materials is still rather challenging, so very few examples of all-organic cells currently exist. Herein, we first present an innovative approach consisting in the substitution of spectator cations and leading to a significant increase of the redox potential of lithiated organic electrode materials thanks to an inductive effect. These results enable developing an all-organic Li-ion battery able to deliver an output voltage above 2.5 V for more than 300 cycles. We then design two p type organic electrode materials able of being charged at low potentials for developing all-organic Anion-ion batteries able to deliver an output voltage at least 1.5 V. Finally, we present a preliminary study of a new family of potentially bipolar compounds

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Slaven, Simon. « Thin film carbon for lithium ion batteries / ». Thesis, Connect to Dissertations & ; Theses @ Tufts University, 1996.

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Thesis (Ph.D.)--Tufts University, 1996.
Adviser: Ronald B. Goldner. Submitted to the Dept. of Electrical Engineering. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;

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Zhao, Kejie. « Mechanics of Electrodes in Lithium-Ion Batteries ». Thesis, Harvard University, 2012. http://dissertations.umi.com/gsas.harvard:10551.

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This thesis investigates the mechanical behavior of electrodes in Li-ion batteries. Each electrode in a Li-ion battery consists of host atoms and guest atoms (Li atoms). The host atoms form a framework, into which Li atoms are inserted via chemical reactions. During charge and discharge, the amount of Li in the electrode varies substantially, and the host framework deforms. The deformation induces in an electrode a field of stress, which may lead to fracture or morphological change. Such mechanical degradation over lithiation cycles can cause the capacity to fade substantially in a commercial battery. We study fracture of elastic electrodes caused by fast charging using a combination of diffusion kinetics and fracture mechanics. A theory is outlined to investigate how material properties, electrode particle size, and charging rate affect fracture of electrodes in Li-ion batteries. We model an inelastic host of Li by considering diffusion, elastic-plastic deformation, and fracture. The model shows that fracture is averted for a small and soft host—an inelastic host of a small feature size and low yield strength. We present a model of concurrent reaction and plasticity during lithiation of crystalline silicon electrodes. It accounts for observed lithiated silicon of anisotropic morphologies. We further explore the microscopic deformation mechanism of lithiated silicon based on first-principles calculations. We attribute to the microscopic mechanism of large plastic deformation to continuous Li-assisted breaking and reforming of Si-Si bonds. In addition, we model the evolution of the biaxial stress in an amorphous Si thin film electrode during lithiation cycle. We find that both the atomic insertion driven by the chemomechanical load and plasticity driven by the mechanical load contribute to reactive flow of lithiated silicon. In such concurrent process, the lithiation reaction promotes plastic deformation by lowering the stress needed to flow. Li-ion battery is an emerging field that couples electrochemistry and mechanics. This thesis aims to understand the deformation mechanism, stresses and fracture associated with the lithiation reaction in Li-ion batteries, and hopes to provide insight on the generic phenomenon that involves interactive chemical reactions and mechanics.
Engineering and Applied Sciences

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Foreman, Evan. « Fluidized Cathodes for Flexible Lithium-Ion Batteries ». University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1493375732158489.

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Croci, Lila. « Gestion de l'énergie dans un système multi-sources photovoltaïque et éolien avec stockage hybride batteries/supercondensateurs ». Phd thesis, Université de Poitiers, 2013. http://tel.archives-ouvertes.fr/tel-00943296.

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Ce mémoire présente le travail de recherche effectué pour la conception d'une stratégie de commande originale, destinée aux systèmes de puissance hybrides en sites isolés. Le système considéré, voué à l'alimentation électrique d'une habitation, comprend deux sources, un groupe de panneaux photovoltaïques et une petite éolienne, et deux types de stockage, un banc de batteries lithium-ion et un de supercondensateurs. Face au problème de gestion de l'énergie dans un système hybride, et aux enjeux de maximisation de sa puissance produite, nous proposons de développer une stratégie de commande basée sur les flux d'énergie. pour cela, nous présentons dans un premier temps les modélisations d'Euler-Lagrange et hamiltonienne du système. Ces modèles permettent d'utiliser la propriété de passivité de celui-ci, et ainsi de synthétiser des commandes par injection d'amortissement pour chaque source, afin de maximiser sa production, et pour les supercondensateurs, dans le but d'assurer une répartition cohérente des flux d'énergie entre eux et les batteries. Les commandes sont finalement mises en œuvre dans un simulateur, puis dans un banc d'essai expérimental, afin d'une part de comparer leurs performances à celles de solutions préexistantes, et d'autre part de valider le bon fonctionnement du système hybride complet les utilisant.

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Hein, Smon [Verfasser]. « Modeling of lithium plating in lithium-ion-batteries / Smon Hein ». Ulm : Universität Ulm, 2018. http://d-nb.info/1162539917/34.

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Damen, Libero <1980&gt. « Advanced lithium and lithium-ion rechargeable batteries for automotive applications ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3427/1/Damen_Libero_Tesi.pdf.

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The worldwide demand for a clean and low-fuel-consuming transport promotes the development of safe, high energy and power electrochemical storage and conversion systems. Lithium-ion batteries (LIBs) are considered today the best technology for this application as demonstrated by the recent interest of automotive industry in hybrid (HEV) and electric vehicles (EV) based on LIBs. This thesis work, starting from the synthesis and characterization of electrode materials and the use of non-conventional electrolytes, demonstrates that LIBs with novel and safe electrolytes and electrode materials meet the targets of specific energy and power established by U.S.A. Department of Energy (DOE) for automotive application in HEV and EV. In chapter 2 is reported the origin of all chemicals used, the description of the instruments used for synthesis and chemical-physical characterizations, the electrodes preparation, the batteries configuration and the electrochemical characterization procedure of electrodes and batteries. Since the electrolyte is the main critical point of a battery, in particular in large- format modules, in chapter 3 we focused on the characterization of innovative and safe electrolytes based on ionic liquids (characterized by high boiling/decomposition points, thermal and electrochemical stability and appreciable conductivity) and mixtures of ionic liquid with conventional electrolyte. In chapter 4 is discussed the microwave accelerated sol–gel synthesis of the carbon- coated lithium iron phosphate (LiFePO 4 -C), an excellent cathode material for LIBs thanks to its intrinsic safety and tolerance to abusive conditions, which showed excellent electrochemical performance in terms of speciﬁc capacity and stability. In chapter 5 are presented the chemical-physical and electrochemical characterizations of graphite and titanium-based anode materials in different electrolytes. We also characterized a new anodic material, amorphous SnCo alloy, synthetized with a nanowire morphology that showed to strongly enhance the electrochemical stability of the material during galvanostatic full charge/discharge cycling. Finally, in chapter 6, are reported different types of batteries, assembled using the LiFePO 4 -C cathode material, different anode materials and electrolytes, characterized by deep galvanostatic charge/discharge cycles at different C-rates and by test procedures of the DOE protocol for evaluating pulse power capability and available energy. First, we tested a battery with the innovative cathode material LiFePO 4 -C and conventional graphite anode and carbonate-based electrolyte (EC DMC LiPF 6 1M) that demonstrated to surpass easily the target for power-assist HEV application. Given that the big concern of conventional lithium-ion batteries is the flammability of highly volatile organic carbonate- based electrolytes, we made safe batteries with electrolytes based on ionic liquid (IL). In order to use graphite anode in IL electrolyte we added to the IL 10% w/w of vinylene carbonate (VC) that produces a stable SEI (solid electrolyte interphase) and prevents the graphite exfoliation phenomenon. Then we assembled batteries with LiFePO 4 -C cathode, graphite anode and PYR 14 TFSI 0.4m LiTFSI with 10% w/w of VC that overcame the DOE targets for HEV application and were stable for over 275 cycles. We also assembled and characterized ―high safety‖ batteries with electrolytes based on pure IL, PYR 14 TFSI with 0.4m LiTFSI as lithium salt, and on mixture of this IL and standard electrolyte (PYR 14 TFSI 50% w/w and EC DMC LiPF 6 50% w/w), using titanium-based anodes (TiO 2 and Li 4 Ti 5 O 12 ) that are commonly considered safer than graphite in abusive conditions. The batteries bearing the pure ionic liquid did not satisfy the targets for HEV application, but the batteries with Li 4 Ti 5 O 12 anode and 50-50 mixture electrolyte were able to surpass the targets. We also assembled and characterized a lithium battery (with lithium metal anode) with a polymeric electrolyte based on poly-ethilenoxide (PEO 20 – LiCF 3 SO 3 +10%ZrO 2 ), which satisfied the targets for EV application and showed a very impressive cycling stability. In conclusion, we developed three lithium-ion batteries of different chemistries that demonstrated to be suitable for application in power-assist hybrid vehicles: graphite/EC DMC LiPF 6 /LiFePO 4 -C, graphite/PYR 14 TFSI 0.4m LiTFSI with 10% VC/LiFePO 4 -C and Li 4 T i5 O 12 /PYR 14 TFSI 50%-EC DMC LiPF 6 50%/LiFePO 4 -C. We also demonstrated that an all solid-state polymer lithium battery as Li/PEO 20 –LiCF 3 SO 3 +10%ZrO 2 /LiFePO 4 -C is suitable for application on electric vehicles. Furthermore we developed a promising anodic material alternative to the graphite, based on SnCo amorphous alloy.

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Damen, Libero <1980&gt. « Advanced lithium and lithium-ion rechargeable batteries for automotive applications ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amsdottorato.unibo.it/3427/.

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The worldwide demand for a clean and low-fuel-consuming transport promotes the development of safe, high energy and power electrochemical storage and conversion systems. Lithium-ion batteries (LIBs) are considered today the best technology for this application as demonstrated by the recent interest of automotive industry in hybrid (HEV) and electric vehicles (EV) based on LIBs. This thesis work, starting from the synthesis and characterization of electrode materials and the use of non-conventional electrolytes, demonstrates that LIBs with novel and safe electrolytes and electrode materials meet the targets of specific energy and power established by U.S.A. Department of Energy (DOE) for automotive application in HEV and EV. In chapter 2 is reported the origin of all chemicals used, the description of the instruments used for synthesis and chemical-physical characterizations, the electrodes preparation, the batteries configuration and the electrochemical characterization procedure of electrodes and batteries. Since the electrolyte is the main critical point of a battery, in particular in large- format modules, in chapter 3 we focused on the characterization of innovative and safe electrolytes based on ionic liquids (characterized by high boiling/decomposition points, thermal and electrochemical stability and appreciable conductivity) and mixtures of ionic liquid with conventional electrolyte. In chapter 4 is discussed the microwave accelerated sol–gel synthesis of the carbon- coated lithium iron phosphate (LiFePO 4 -C), an excellent cathode material for LIBs thanks to its intrinsic safety and tolerance to abusive conditions, which showed excellent electrochemical performance in terms of speciﬁc capacity and stability. In chapter 5 are presented the chemical-physical and electrochemical characterizations of graphite and titanium-based anode materials in different electrolytes. We also characterized a new anodic material, amorphous SnCo alloy, synthetized with a nanowire morphology that showed to strongly enhance the electrochemical stability of the material during galvanostatic full charge/discharge cycling. Finally, in chapter 6, are reported different types of batteries, assembled using the LiFePO 4 -C cathode material, different anode materials and electrolytes, characterized by deep galvanostatic charge/discharge cycles at different C-rates and by test procedures of the DOE protocol for evaluating pulse power capability and available energy. First, we tested a battery with the innovative cathode material LiFePO 4 -C and conventional graphite anode and carbonate-based electrolyte (EC DMC LiPF 6 1M) that demonstrated to surpass easily the target for power-assist HEV application. Given that the big concern of conventional lithium-ion batteries is the flammability of highly volatile organic carbonate- based electrolytes, we made safe batteries with electrolytes based on ionic liquid (IL). In order to use graphite anode in IL electrolyte we added to the IL 10% w/w of vinylene carbonate (VC) that produces a stable SEI (solid electrolyte interphase) and prevents the graphite exfoliation phenomenon. Then we assembled batteries with LiFePO 4 -C cathode, graphite anode and PYR 14 TFSI 0.4m LiTFSI with 10% w/w of VC that overcame the DOE targets for HEV application and were stable for over 275 cycles. We also assembled and characterized ―high safety‖ batteries with electrolytes based on pure IL, PYR 14 TFSI with 0.4m LiTFSI as lithium salt, and on mixture of this IL and standard electrolyte (PYR 14 TFSI 50% w/w and EC DMC LiPF 6 50% w/w), using titanium-based anodes (TiO 2 and Li 4 Ti 5 O 12 ) that are commonly considered safer than graphite in abusive conditions. The batteries bearing the pure ionic liquid did not satisfy the targets for HEV application, but the batteries with Li 4 Ti 5 O 12 anode and 50-50 mixture electrolyte were able to surpass the targets. We also assembled and characterized a lithium battery (with lithium metal anode) with a polymeric electrolyte based on poly-ethilenoxide (PEO 20 – LiCF 3 SO 3 +10%ZrO 2 ), which satisfied the targets for EV application and showed a very impressive cycling stability. In conclusion, we developed three lithium-ion batteries of different chemistries that demonstrated to be suitable for application in power-assist hybrid vehicles: graphite/EC DMC LiPF 6 /LiFePO 4 -C, graphite/PYR 14 TFSI 0.4m LiTFSI with 10% VC/LiFePO 4 -C and Li 4 T i5 O 12 /PYR 14 TFSI 50%-EC DMC LiPF 6 50%/LiFePO 4 -C. We also demonstrated that an all solid-state polymer lithium battery as Li/PEO 20 –LiCF 3 SO 3 +10%ZrO 2 /LiFePO 4 -C is suitable for application on electric vehicles. Furthermore we developed a promising anodic material alternative to the graphite, based on SnCo amorphous alloy.

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Toigo, Christina Verena <1986&gt. « Towards eco-friendly batteries : concepts for lithium and sodium ion batteries ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10067/1/Thesis%20CT_final.pdf.

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Several possibilities are arising aiming the development of “greener”, more sustainable energy storage systems. One point is the completely water-based processing of battery electrodes, thus being able to renounce the use of toxic solvents in the preparation process. Despite its advantage of lower cost and eco-friendlyness, there is the need of similar mechanical and electrochemichal behavior for boosting this preparation mode. Another point – accompanying the water-based processing - is the replacement of solvent-based polymer binders by water-based ones. These binders can be based on fluorinated, crude-oil based polymers on the one side, but also on naturally abundant and economic friendly biopolymers. The most common anode materials, graphite and lithium titanate (LTO), have been subjected a water-based preparation route with different binder systems. LTO is a promising anode material for lithium ion batteries (LIBs), as it shows excellent safety characteristics, does not form a significant SEI and its volume change upon intercalation of lithium ions is negligible. Unfortunately, this material suffers from a rather low electric conductivity - that is why an intensive study on improved current collector surfaces for LTO electrodes was performed. In order to go one step ahead towards sustainable energy storage, anode and cathode active materials for a sodium ion battery were synthesized. Anode active material resulted in a successful product which was then subjected to further electrochemical tests. In this PhD work the development of “greener” energy storage possibilities is tested under several aspects. The ecological impact of raw materials and required battery components is examined in detail.

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GENTILE, ANTONIO. « MXene-based materials for alkaline-ion batteries : synthesis, properties, applications ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/382748.

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La produzione sempre maggiore di dispositivi portatili e auto elettriche chiede al mercato di produrre dispositivi efficienti in grado di poter accumulare l’energia elettrica. Per questo tipo di tecnologie in cui la miniaturizzazione del dispositivo è essenziale, le batterie litio ione (LIBs) sono diventate il mezzo di accumulare energia. La ricerca su queste batterie è focalizzata ad ottenere dispositivi sempre più performanti con materiali elettrodici ad alte capacità gravimetriche e volumetriche. Accanto all’aspetto tecnologico, legato alla ottimizzazione dei materiali, vi è anche quello dell’approvvigionamento dei componenti attivi della batteria, tra tutti il litio. La problematica attualmente è affrontata studiando batterie con altri metalli alcalini (Na e K). Di questi dispositivi non esistono però materiali già standardizzati malgrado la ricerca, specialmente sulle batterie sodio ione (SIB), sia partita solo qualche anno più tardi rispetto quella delle LIB; per cui queste tecnologie oggi sono destinate ad affiancare quelle delle LIB per sopperire all’enorme richiesta di mercato di batterie per i veicoli del futuro. L’obbiettivo del presente lavoro è stato quello di sviluppare materiali anodici a base di MXene per ottenere efficienti anodi per batterie sodio e litio ione. I MXenes sono una famiglia di carburi di metalli di transizione con una struttura 2D che sembrerebbe promettente per l’intercalazione di diversi ioni grazie ad una grande flessibilità ed adattabilità strutturale nei confronti del tipo di ione intercalante. L’intercalazione degli ioni avviene con un meccanismo pseudocapacitivo per cui i materiali hanno capacità limitate, ma hanno grande stabilità elettrochimica su migliaia di cicli ed efficienze coulombiche prossime al 100%. La produzione di questo materiale avviene per etching in HF di un precursore chiamato MAX phase. Questo è il metodo più facile e veloce per ottenere il materiale in scala di laboratorio ma presenta numerose criticità quando i volumi vengono rapportati su scala industriale. Una gran parte del lavoro è stata dedicata allo studio della tecnica sintetica per ottenere MXenes per SIB riducendo o sostituendo HF nella sintesi chimica. I materiali sono stati caratterizzati con varie tecniche di caratterizzazioni strutturali, morfologiche ed elettrochimiche. Data la struttura 2D, che ricorda quella del grafene, un uso frequente in letteratura è quello della realizzazioni di nanocompositi per SIB e LIB, al fine di produrre materiali ad alta capacità, come richiesto nel mercato delle batterie. Sono stati quindi ottenuti dei nanocompositi a base di antimonio-MXene e ossido di stagno-MXene testati rispettivamente in SIB e LIB. Antimonio e ossido di stagno sono due materiale dalla elevata capacità teorica, quando usati come anodi in batterie, ma allo stesso tempo sono estremamente fragili e tendono a polverizzarsi nei processi di carica e scarica. Il MXene è servito da buffer per limitare o evitare la frattura e distacco delle leghe dalla superficie elettrodica
The ever-increasing production of portable devices and electric cars asks to the market to produce efficient devices that can store electrical energy. For these types of technologies, where device miniaturization is essential, lithium-ion batteries (LIBs) have become leaders as energy storage systems. The research on the lithium-ion batteries is focused to obtain more performing devices with high gravimetric and volumetric capacities of the electrode materials. In addition to the technological aspect, related to the optimization of materials, there is the supply chain of active components of the battery to consider, starting from lithium. At the moment, the problem is tackled by studying batteries with other alkaline metal ions, i.e. Na+ and K+. However, there are no standardized active materials for these devices, especially on sodium-ion batteries (SIBs), started only a few years later than that of LIBs; therefore, today these technologies are intended to support the LIBs in order to satisfy the enormous market demand of the batteries for the future vehicles. The goal of this work was to develop MXene-based anode materials to obtain efficient anodes for sodium and lithium-ion batteries. MXenes are a family of inorganic transition metal carbides, nitrides, and carbonitrides with a 2D structure that would seem promising for the intercalation of different ions due to a great flexibility and adaptability towards several intercalating ions. The ion intercalations occur by a pseudocapacitive mechanism whereby the materials have limited capacity, but they have great electrochemical stability over thousands of cycles and coulombic efficiencies near to 100%. The production of this material was done by HF etching of a precursor called MAX phase. This is the easiest and fastest method to obtain the material in laboratory scale, but it has many criticalities when the process has to be scale-up to industrial scale. A large part of this work was spent studying the synthetic technique to obtain MXenes for SIB by reducing or replacing HF in the chemical synthesis. The materials have been characterized by various techniques such as X-ray diffractometry, electron microscopy, X-ray photoelectron spectroscopy, etc., and by electrochemical tests, such as cyclic voltammetry and galvanostatic cycling. Thanks to the 2D structure, a common use of MXene in the literature is in nanocomposite syntheses for SIBs and LIBs, in order to produce high-capacity materials, as required in the battery market. Therefore, two nanocomposites based on antimony-MXene and tin oxide-MXene tested for SIB and for LIB respectively, were synthesized. Antimony and tin oxide are two materials with high theoretical capacity when used as anodes in batteries, but at the same time, they are extremely fragile and tend to pulverize during charging and discharging processes. MXene is used as a buffer to limit or prevent cracking and separation of alloys from the electrode surface.

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Ponnuchamy, Veerapandian. « Towards A Better Understanding of Lithium Ion Local Environment in Pure, Binary and Ternary Mixtures of Carbonate Solvents : A Numerical Approach ». Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GRENY004/document.

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En raison de l'augmentation de la demande d'énergie, ressources écologiques respectueux de l'environnement et durables (solaires, éoliennes) doivent être développées afin de remplacer les combustibles fossiles. Ces sources d'énergie sont discontinues, étant corrélés avec les conditions météorologiques et leur disponibilité est fluctuant dans le temps. En conséquence, les dispositifs de stockage d'énergie à grande échelle sont devenus incontournables, pour stocker l'énergie sur des échelles de temps longues avec une bonne compatibilité environnementale. La conversion d'énergie électrochimique est le mécanisme clé pour les développements technologiques des sources d'énergie alternatives. Parmi ces systèmes, les batteries Lithium-ion (LIB) ont démontré être les plus robustes et efficaces et sont devenus la technologie courante pour les systèmes de stockage d'énergie de haute performance. Ils sont largement utilisés comme sources d'énergie primaire pour des applications populaires (ordinateurs portables, téléphones cellulaires, et autres). La LIB typique est constitué de deux électrodes, séparés par un électrolyte. Celui-ci joue un rôle très important dans le transfert des ions entre les électrodes fournissant la courante électrique. Ce travail de thèse porte sur les matériaux complexes utilisés comme électrolytes dans les LIB, qui ont un impact sur les propriétés de transport du ion Li et les performances électrochimiques. Habituellement l'électrolyte est constitué de sels de Li et de mélanges de solvants organiques, tels que les carbonates cycliques ou linéaires. Il est donc indispensable de clarifier les propriétés structurelles les plus importantes, et leurs implications sur le transport des ions Li+ dans des solvants purs et mixtes. Nous avons effectué une étude théorique basée sur la théorie du fonctionnelle densité (DFT) et la dynamique moléculaire (MD), et nous avons consideré des carbonates cyclique (carbonate d'éthylène, EC, et carbonate de propylène, PC) et le carbonate de diméthyle, DMC, linéaire. Les calculs DFT ont fourni une image détaillée des structures optimisées de molécules de carbonate et le ion Li+, y compris les groupes pures Li+(S)n (S =EC,PC,DMC et n=1-5), groupes mixtes binaires, Li+(S1)m(S2)n (S1,S2=EC,PC,DMC, m+n=4), et ternaires Li+(EC)l(DMC)m(PC)n (l+m+n=4). L'effet de l'anion PF6 a également été étudié. Nous avons aussi étudié la structure de la couche de coordination autour du Li+, dans tous les cas. Nos résultats montrent que les complexes Li+(EC)4, Li+(DMC)4 et Li+(PC)3 sont les plus stables, selon les valeurs de l'énergie libre de Gibbs, en accord avec les études précédentes. Les énergies libres de réactions calculés pour les mélanges binaires suggèrent que l'ajout de molécules EC et PC aux clusters Li+ -DMC sont plus favorables que l'addition de DMC aux amas Li+-EC et Li+-PC. Dans la plupart des cas, la substitution de solvant aux mélanges binaires sont défavorables. Dans le cas de mélanges ternaires, la molécule DMC ne peut pas remplacer EC et PC, tandis que PC peut facilement remplacer EC et DMC. Notre étude montre que PC tend à substituer EC dans la couche de solvation. Nous avons complété nos études ab-initio par des simulations MD d'une ion Li immergé dans les solvants purs et dans des mélanges de solvants d'intérêt pour les batteries, EC:DMC(1: 1) et EC:DMC:PC(1:1:3). MD est un outil très puissant et nous a permis de clarifier la pertinence des structures découvertes par DFT lorsque le ion est entouré par des solvants mélangés. En effet,la DFT fournit des informations sur les structures les plus stables de groupes isolés, mais aucune information sur leur stabilité ou de la multiplicité (entropie) lorsqu'il est immergé dans un environnement solvant infinie. Les données MD, ainsi que les calculs DFT nous ont permis de donner une image très complète de la structure locale de mélanges de solvants autour le ion lithium, sensiblement amélioré par rapport aux travaux précédents
Due to the increasing global energy demand, eco-friendly and sustainable green resources including solar, or wind energies must be developed, in order to replace fossil fuels. These sources of energy are unfortunately discontinuous, being correlated with weather conditions and their availability is therefore strongly fluctuating in time. As a consequence, large-scale energy storage devices have become fundamental, to store energy on long time scales with a good environmental compatibility. Electrochemical energy conversion is the key mechanism for alternative power sources technological developments. Among these systems, Lithium-ion (Li+) batteries (LIBs) have demonstrated to be the most robust and efficient, and have become the prevalent technology for high-performance energy storage systems. These are widely used as the main energy source for popular applications, including laptops, cell phones and other electronic devices. The typical LIB consists of two (negative and positive) electrodes, separated by an electrolyte. This plays a very important role, transferring ions between the electrodes, therefore providing the electrical current. This thesis work focuses on the complex materials used as electrolytes in LIBs, which impact Li-ion transport properties, power densities and electrochemical performances. Usually, the electrolyte consists of Li-salts and mixtures of organic solvents, such as cyclic or linear carbonates. It is therefore indispensable to shed light on the most important structural (coordination) properties, and their implications on transport behaviour of Li+ ion in pure and mixed solvent compositions. We have performed a theoretical investigation based on combined density Functional Theory (DFT) calculations and Molecular Dynamics (MD) simulations, and have focused on three carbonates, cyclic ethylene carbonate (EC) and propylene carbonate (PC), and linear dimethyl carbonate (DMC). DFT calculations have provided a detailed picture for the optimized structures of isolated carbonate molecules and Li+ ion, including pure clusters Li+(S)n (S=EC, PC, DMC and n=1-5), mixed binary clusters, Li+(S1)m(S2)n (S1, S2 =EC, PC, DMC, with m+n=4), and ternary clusters Li+(EC)l(DMC)m(PC)n with l+m+n=4. Pure solvent clusters were also studied including the effect of PF6- anion. We have investigated in details the structure of the coordination shell around Li+ for all cases. Our results show that clusters such as Li+(EC)4, Li+(DMC)4 and Li+(PC)3 are the most stable, according to Gibbs free energy values, in agreement with previous experimental and theoretical studies. The calculated Gibbs free energies of reactions in binary mixtures suggest that the addition of EC and PC molecules to the Li+-DMC clusters are more favourable than the addition of DMC to Li+-EC and Li+-PC clusters. In most of the cases, the substitution of solvent to binary mixtures are unfavourable. In the case of ternary mixtures, the DMC molecule cannot replace EC and PC, while PC can easily substitute both EC and DMC molecules. Our study shows that PC tends to substitute EC in the solvation shell. We have complemented our ab-initio studies by MD simulations of a Li-ion when immersed in the pure solvents and in particular solvents mixtures of interest for batteries applications, e.g. , EC:DMC (1:1) and EC:DMC:PC(1:1:3). MD is a very powerful tool and has allowed us to clarify the relevance of the cluster structures discovered by DFT when the ion is surrounded by bulk solvents. Indeed, DFT provides information about the most stable structures of isolated clusters but no information about their stability or multiplicity (entropy) when immersed in an infinite solvent environment. The MD data, together the DFT calculations have allowed us to give a very comprehensive picture of the local structure of solvent mixtures around Lithium ion, which substantially improve over previous work

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Chaouachi, Oumaima. « Up-scaling methodology for lithium-ion battery modelling ». Thesis, Université Grenoble Alpes, 2021. http://www.theses.fr/2021GRALI011.

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La technologie des batteries Lithium-ion bénéficie aujourd'hui d'un grand succès et est largement utilisée dans diverses technologies portatives, pour le transport et les réseaux. Néanmoins, au vue de la diversité des chimies des batteries Li-ion et des nombreux mécanismes de vieillissement, il est primordial pour les concepteursde modules de batterie d'avoir recours à la simulation des performances et du vieillissement afin de satisfaire le cahier des charges desmodules développés. Les cellules Li-ions sont des systèmes multi-physiques par essence, où des modifications aux échelles microscopiques impactent fortement les caractéristiques globales de la cellule. Les modèles mathématiques de ces systèmes doivent donc être capables de lier ces caractéristiques globales à la description des phénomènes physiques aux échelles microscopiques. L'objectif principal de cette thèse est de mettre au point une méthodologie de remontée d'échelle mathématique permettant de faire le lien entre des modèles physiques aux échelles microscopiques et des modèles simplifiés de type circuit électrique équivalent, utilisés lors de la conception de modules. Cette méthodologie sera mise en œuvre à partir des modèles physiques aux échelles fines et validée en s'appuyant sur des données expérimentales obtenues sur des cellules en début de vie et vieillies sous différentes conditions
Li-ion battery technology has a great success and is widely used in various portable technologies and for transport. However, giving the diversity of battery chemistry and the numerous aging phenomena, it remains critical for battery pack designers to resort to simulation of battery performance and aging in order to optimize the module design. Li-ion batteries are multiscale systems where modifications at microscopic length scales have a large impact on global cell characteristics. Mathematical models of these systems must therefore be able to link the global cell characteristics to the description of the physical phenomena at microscopic scales. The aim of the thesis is to develop an up-scaling methodology able to connect the microscopic multi-physic models to the simplified equivalent electrical circuit models used by battery module's designers. This up-scaling methodology will be implemented based on physical model at the electrode scale and validated with experimental measurements in the beginning of life of the battery and during its lifetime

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Deng, Junwen. « Strain engineered nanomembranes as anodes for lithium ion batteries ». Doctoral thesis, Universitätsbibliothek Chemnitz, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-159972.

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Lithium ion batteries (LIBs) have attracted considerable interest due to their wide range of applications, such as portable electronics, electric vehicles (EVs) and aerospace applications. Particularly, the emergence of a variety of nanostructured materials has driven the development of LIBs towards the next generation, which is featured with high specific energy and large power density. Herein, rolled-up nanotechnology is introduced for the design of strain-released materials as anodes of LIBs. Upon this approach, self-rolled nanostructures can be elegantly combined with different functional materials and form a tubular shape by relaxing the intrinsic strain, thus allowing for enhanced tolerance towards stress cracking. In addition, the hollow tube center efficiently facilitates electrolyte mass flow and accommodates volume variation during cycling. In this context, such structures are promising candidates for electrode materials of LIBs to potentially address their intrinsic issues. This work focuses on the development of superior structures of Si and SnO2 for LIBs based on the rolled-up nanotech. Specifically, Si is the most promising substitute for graphite anodes due to its abundance and high theoretical gravimetric capacity. Combined with the C material, a Si/C self-wound nanomembrane structure is firstly realized. Benefiting from a strain-released tubular shape, the bilayer self-rolled structures exhibit an enhanced electrochemical behavior over commercial Si microparticles. Remarkably, this behavior is further improved by introducing a double-sided carbon coating to form a C/Si/C self-rolled structure. With SnO2 as active material, an intriguing sandwich-stacked structure is studied. Furthermore, this novel structure, with a minimized strain energy due to strain release, exposes more active sites for the electrochemical reactions, and also provides additional channels for fast ion diffusion and electron transport. The electrochemical characterization and morphology evolution reveal the excellent cycling performance and stability of such structures.

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Chen, Mengyuan. « A Closed Loop Recycling Process for the End-of-Life Electric Vehicle Li-ion Batteries ». Digital WPI, 2020. https://digitalcommons.wpi.edu/etd-dissertations/605.

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Lithium-ion batteries (LIBs) play a significant role in our highly electrified world and will continue to lead technology innovations. Millions of vehicles are equipped with or directly powered by LIBs, mitigating environmental pollution and reducing energy use. This rapidly increasing use of LIBs in vehicles will introduce a large quantity of spent LIBs within an 8- to10-year span and proper handling of end-of-life (EOL) vehicle LIBs is required. Over the last several years, the Worcester Polytechnic Institute (WPI) team in the Department of Mechanical Engineering has developed a closed-loop lithium ion battery recycling process and it has been demonstrated that the recovered NMC 111 has similar or better electrochemical properties than the commercial control powder with both coin cells and pouch cells, which have been independently tested by A123 Systems and Argonne National Laboratory. In addition, the different chemical compositions of the incoming recycling streams were shown to have little observed effects on the recovered precursor and resultant cathode material. Therefore, the WPI-developed process applies to different spent Li-ion battery waste streams and is, therefore, general. During the last few years, industry has the tendency to employ higher-nickel and lower-cobalt cathode material since it can provide higher capacity and energy density and lower cost. However, higher-nickel cathode material has the intrinsic unstable properties and surface modifications can be applied to slow down its degradation. Here, two facile scalable Al2O3 coating methods (dry coating and wet coating) were applied to recycled NMC 622 and the resultants were systematically studied. The Al-rich layer from the dry coating process imparted improved structural and thermal stability in accelerated cycling performed at 45 °C between 3.0 and 4.3 V, and the capacity retention of pouch cells with dry coated NMC 622 (D-NMC) cathode increased from 83% to 91% compared to Al-free NMC 622 after 300 cycles. However, for wet coated NMC 622 (W-NMC), the increased surface area accompanying by formation of NiO rock-salt like structure could have negative impacts on the cycling performance. There exist three challenges for current LIBs’ recycling research. First of all, most of the research is done in lab-scale and the scale-up ability needs to be proven. The scale-up ability of our recycling process has been verified by our scale-up experiments. The second challenge resides in the flexibility, here once again, with our intentionally designed experiments that having various incoming chemistries, the flexibility is validated. The last challenge is the lack of reliable testing because most of the testing is conducted with coin cells. Coin cells are relatively simple format and lacks persuasion. Here, with various industrial-level cell formats that ranging from coin cell, single layer pouch cell, 1Ah cell and 11Ah cell, a reliable and trustworthy testing is established. With this validation, the hesitation of recruiting recycled materials into industry shouldn’t exist.

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Yao, Yueping Jane. « Carbon based anode materials for lithium-ion batteries ». Access electronically, 2003. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20050111.120602/index.html.

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Hellqvist, Kjell Maria. « Performance of Conventional and Structural Lithium-Ion Batteries ». Doctoral thesis, KTH, Tillämpad elektrokemi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-122875.

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Lithium-ion batteries have, in recent years, experienced a rapid development from small everyday devices towards hybrid electric vehicle (HEV) applications. Due to this shift in application area, the battery performance andits degradation with time are becoming increasingly important issues to besolved.In this thesis, lithium-ion batteries are investigated with focus on lifetime performance of an existing battery chemistry, and development of electrodes for so-called structural batteries. The systems are evaluated by electrochemical methods, such as cycling and electrochemical impedance spectroscopy (EIS),combined with material characterization and modeling. Lifetime performance of mesocarbon microbeads (MCMB)/LiFePO4 cells was investigated to develop an understanding of how this technology tolerates and is influenced by different conditions, such as cycling, storage and temperature.The lifetime of the LiFePO4-based cells was found to be significantly reduced by cycling at elevated temperature, almost five times shorter compared to cycle-aged cells at ambient temperature. The calendar-aged cells also showed major signs of degradation at elevated temperatures. The overall cause of aging was electrolyte decomposition which resulted in loss of cyclable lithium, i.e. capacity fade, and impedance increase. Commercially available polyacrylonitrile (PAN)-based carbon fibers were investigated, both electrochemically and mechanically, to determine their suitability as negative electrodes in structural batteries. The electrochemical performance of carbon fibers was found to be excellent compared to other negative electrode materials, especially for single or well-separated fibers. The mechanical properties, measured as changes in the tensile properties, showed that the tensile stiffness was unaffected by lithium-ion intercalation and cycling. The ultimate tensile strength, however, showed a distinct variation with state-of-charge (SOC). Overall, carbon fibers are suitable for structural battery applications.

QC 20130529

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Ren, Shengru. « A nonlinear circuit model for lithium-ion batteries ». Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/45621.

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Drewett, Nicholas E. « Novel routes to high performance lithium-ion batteries ». Thesis, University of St Andrews, 2013. http://hdl.handle.net/10023/3513.

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This thesis investigates several approaches to the development of high-performance batteries. A general background to the field and an introduction to the experimental methods used are given in Chapters 1 and 2 respectively. Chapter 3 presents a study of ordered and disordered LiNi₀.₅Mn₁.₅O₄ materials produced using an optimised resorcinol-formaldehyde gel (R-F gel) synthetic technique. Both materials exhibited good electrochemical properties and minimal side reaction with the electrolyte. Structural analyses of the materials in various states of discharge and charge were undertaken, and from these the charge / discharge processes were elucidated. In chapter 4 R-F gel synthesised Li(Ni₁/₃Mn₁/₃Co₁/₃)O₂ is studied and found to exhibit a high degree of structural stability on cycling, as well as excellent capacity, cyclability and rate capability. Photoelectron spectroscopy studies revealed that the R-F gel derived particles have highly stable surfaces. A discussion of the results and their significance, with particular regard to the outstanding electrochemical performance observed, is also presented. Chapter 5 sets out an investigation into the nature of R-F gel synthesised 0.5Li₂MnO₃:0.5LiNi₁/₃Mn₁/₃Co₁/₃O₂. The electrochemical data revealed that, after an initial activation stage, the R-F gel derived material exhibited a high capacity, good cyclability and exceptional rate capability. This chapter also considers some initial structural investigations and the electrochemical processes occurring on charge. In chapter 6 the use of ether-based electrolytes, combined with various cathode materials, in lithium-oxygen batteries is examined. The formation of decomposition products was observed, and a scheme suggesting probable reaction pathways is given. It was noted that significant quantities of the desired discharge product, lithium peroxide, were formed on the 1st cycle discharge, implying some electrolyte / cathode combinations do demonstrate a degree of stability. A summary of the results and a discussion of their significance are also included.

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Klett, Matilda. « Electrochemical Studies of Aging in Lithium-Ion Batteries ». Doctoral thesis, KTH, Tillämpad elektrokemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-145057.

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Lithium-ion batteries are today finding use in automobiles aiming at reducing fuel consumption and emissions within transportation. The requirements on batteries used in vehicles are high regarding performance and lifetime, and a better understanding of the interior processes that dictate energy and power capabilities is a key to strategic development. This thesis concerns aging in lithium-ion cells using electrochemical tools to characterize electrode and electrolyte properties that affect performance and performance loss in the cells. A central difficulty regarding battery aging is to manage the coupled effects of temperature and cycling conditions on the various degradation processes that determine the lifetime of a cell. In this thesis, post-mortem analyses on harvested electrode samples from small pouch cells and larger cylindrical cells aged under different conditions form the basis of aging evaluation. The characterization is focused on electrochemical impedance spectroscopy (EIS) measurements and physics-based EIS modeling supported by several material characterization techniques to investigate degradation in terms of properties that directly affect performance. The results suggest that increased temperature alter electrode degradation and limitations relate in several cases to electrolyte transport. Variations in electrode properties sampled from different locations in the cylindrical cells show that temperature and current distributions from cycling cause uneven material utilization and aging, in several dimensions. The correlation between cell performance and localized utilization/degradation is an important aspect in meeting the challenges of battery aging in vehicle applications. The use of in-situ nuclear magnetic resonance (NMR) imaging to directly capture the development of concentration gradients in a battery electrolyte during operation is successfully demonstrated. The salt diffusion coefficient and transport number for a sample electrolyte are obtained from Li+ concentration profiles using a physics-based mass-transport model. The method allows visualization of performance limitations and can be a useful tool in the study of electrochemical systems.

QC 20140512

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Tsikourkitoudi, Vasiliki P. « Development of advanced nanomaterials for lithium-ion batteries ». Thesis, Kingston University, 2016. http://eprints.kingston.ac.uk/37347/.

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The scope of the present study was to demonstrate the capability of Flame Spray Pyrolysis (FSP) process as a unique facility for the one-step synthesis of lithium titanate (Li[sub]4Ti[sub]5O[sub]12, LTO) nanoparticles with tailored properties. FSP offers a versatile technology to produce a wide range of high-purity oxide nanoparticles with desired properties. The ability of FSP to manipulate nanoparticles' properties was demonstrated by controlling operating conditions and selecting appropriate precursors. More precisely, the effect of FSP processing conditions on LTO properties were thoroughly investigated both experimentally in a pilot-scale reactor (production rates up to 1 kg h[sup]-1) and theoretically by the development of models describing particle dynamics in the spray flame. The main aim was to obtain LTO nanoparticles of different particle sizes. The produced nanoparticles were used as active materials for the fabrication of lithium-ion battery anodes and electrochemical characterisation was performed in order to examine the influence of the particles' physical properties on the battery performance. The control of the flame synthesis parameters is crucial, since the properties of the final product depend on the nanoparticles' size distribution, morphology, extent of agglomeration, as well as phase compostition. Initially, the influence of liquid feed properties (precursor concentration and solvent) on LTO physical properties was established. LTO particle size increazsed when the precursor concentration was increased due to particle concentration increase in the flame followed by the enhancement of particle collisions and hence particle growth. Moreover, high precursor concentration caused a variation of physical properties of the precursor mixture, affecting the atomisation process, and subsequently led to the formation of larger droplets. Larger droplets generated larger particle. Additionally, the choice of solvent for the dissolution of metal precursors was proven to be an important issue for LTO synthesis by FSP. The physical properties of the solvents in relation to metal precursor properties affected the formation of LTO nanoparticles. Inhomogenous particle size distribution was observed for LTO synthesised by a precursor mixture containing isopropanoil, due to its low boiling point inducing particle formation via droplet-to-particle mechanism, whereas pure 2-ethylhexanoic acid was used, LTO particles were formed by gas-to-particle route and had homogenous size distribution. The droplets generated during atomisation by the precursor solution of pure 2- ethylhexanoic acid had the largest diameter due to the high viscosity and density of the mixture. Despite this, the obtained nanoparticles were the smallest in comparison to those obtained from other precursor solutions. In such cases, the boiling point and specific combustion enthalpy of the solvents should be taken into consideration. Apart from the liquid feed properties, the effect of FSP operating conditions (O[sub]2 dispersion gas and precursor flow rate) were also investigated in the present study. By increasing the O[sub]2 dispersion gas rate, LTO nanoparticles' diameter was decreased due to a decrease of the droplet diameter. Particle sintering was also prevented due to the faster transport of primary particles through a shorter flame. An increase of the precursor flow rate at first increased and then decreased the LTO nanoparticles' size. The initial increase of particle size occurred due to a flame temperature increase. At higher precursor flow rates, the droplets disintegrated and generated many smaller fragmented droplets due to higher temperature, which subsequently formed smaller particles. Moreover, particle growth in the spray flames was studied theoretically, and numerical models were developed. The monodisperse model developed assumed that all primary particles had the same size. However, it overestimated the primary particle diameter values. Polydispersity was taken into consideration in the development of an additional model which was solved by the quadrature method of moments. The results obtained from the polydisperse model were closer to the experimental values, both for low and high production rates. Finally, the synthesised LTO nanoparticles were used as active materials in lithium-ion battery half cells and their electrochemical behaviour was elucidated, demonstrating the effect of the particles' physical properties on their electrochemical performance. LTO of particle size 18 and 21 nm showed the best electrochemical performance with capacity retention of almost 100% after 500 cycles, whereas the smallest particle deteriorated the electrochemical performance with a capacity loss of more than 60%.

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Khomenko, V. G., I. V. Senyk et V. Z. Barsukov. « Advanced nanostructured anode materials for lithium-ion batteries ». Thesis, Sumy State University, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20598.

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The more popular active material for negative electrode is usually flake graphite due to its excellent cycle life (up to 1000 cycles). The main disadvantage of graphite is a relatively low specific capacity, because even the theoretical value is QCth = 372 mA.h/g. Si, Sn, Al, hard carbons and some other materials are actively investigated as the alternate materials for lithium-ion batteries. However, they have not received a practical application, since their large theoretical capacity is accompanied by sharp drop of capacity (during the few cycles), high irreversible capacity (up to 50 % and more), nonhorizontal shape of charge–discharge curves. The main reason of sharp capacity degradation is considerable (in 2-4 times) volume changes of these materials during intercalation- deintercalation of lithium ions. We have formulated some theoretical principles and developed the experimental composite nanostructured anode materials for lithium-ion batteries with high level of specific capacity (up to 600 mA.h/g), quite stable cyclization, minimal irreversible capacity (ca 8 %), horizontal shape of charge–discharge curves. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/20598

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Cheekati, Sree Lakshmi. « GRAPHENE BASED ANODE MATERIALS FOR LITHIUM-ION BATTERIES ». Wright State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=wright1302573691.

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Sharma, Kripa. « Bilevel Equalizer Drivers for Large Lithium-Ion Batteries ». University of Toledo / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1564677943667852.

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Sotta, Dane. « Liquides ioniques gélifiés pour les batteries lithium-ion ». Amiens, 2011. http://www.theses.fr/2011AMIE0115.

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Les systèmes de stockage de l'énergie électrique au lithium sont prometteurs pour les applications "transport" (véhicules électrifiés). Dans ces batteries, la nature de l'électrolyte conditionne la gamme de température de fonctionnement et la sûreté du système. Ce travail de recherche s'inscrit dans ce contexte et porte sur l'étude de nouveaux électrolytes gélifiés pour batteries Li-ion. La première phase de ce travail a été consacrée à la formulation et caractérisation d'électrolytes gélifiés constitués d'un réseau polymère de type époxy-amine, d'un liquide ionique et d'un sel de lithium. Les propriétés physico-chimiques de ces systèmes ternaires ont été discutées en fonction de leur composition. Des valeurs de conductivité ionique satisfaisantes pour l'application visée ont été mesurées pour des gels fortement chargés en liquide ionique. Des membranes d'électrolytes gélifiés ont été mises en œuvre en assemblages avec des électrodes à insertion et leurs propriétés électrochimiques ont été caractérisées dans des cellules prototypes. Parallèlement, une étude plus fondamentale a été engagée pour investiguer les phénomènes de transport des espèces chargées au sein des gels. Au delà des mesures classiques basées sur la spectroscopie d'impédance électrochimique, l'utilisation de plusieurs méthodes de spectroscopie par Résonance Magnétique Nucléaire a mis en évidence l'existence d'interactions locales entre la résine et les ions lithium, impactant sensiblement leur mobilité. Ce travail a permis de faire le lien entre les interactions moléculaires et les propriétés électriques et, ainsi, de mieux comprendre les limitations propres aux systèmes choisis pour dégager des pistes d'amélioration de leurs propriétés
Lithium batteries are promising electrical energy storage devices for application in electric vehicles. In these systems the nature of the electrolyte is a key point to control the temperature range of use and the security conditions of the battery. In this context, this work is aimed at developing new gel polymer electrolytes for lithium-ion batteries. The first part of this study has been devoted to formulation and characterization of gelled electrolytes based on an epoxy-amine resin, an ionic liquid and a lithium salt. Physico-chemical properties of these ternary systems have been discussed according to their composition. Gels with high ionic liquid contents exhibit satisfactory ionic conductivity for the considered application. Gel polymer membranes have ben processed and coupled to insertion electrodes to study their electrochemical properties in appropriate prototype cells. In a parallel study, we have focused our investigation on transport properties of charged species in these gels. Besides classical measurements based on Electrochemical Impedance Spectroscopy, several Nuclear Magnetic Resonance Spectroscopy methods have been implemented to study local and long range ion mobility. They have shown that particular interactions are established in the gels between the resin and the lithium ions with reduced mobility for the latter. This work has highlighted the link between molecular interactions and electrical properties in the ternary gels and thus it has enabled a better knowledge of the inner limitations of these systems. Finally, further routes have been proposed to optimize gel polymer electrolytes in lithium-ion batteries

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Reynier, Yvan. « Thermodynamique et cinétique d'électrodes pour batteries lithium-ion ». Grenoble INPG, 2005. http://www.theses.fr/2005INPG0039.

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L’évolution structurale dans les électrodes pour batteries Lithium ion est un problème central pour la compréhension de leur comportement électrochimique. Dans cette étude un nouveau système utilisant la variation du potentiel d’abandon en fonction de la température a été développé pour déterminer l’entropie et l’enthalpie d’intercalation du lithium. La diffraction des rayons X a également été utilisée pour corréler ces résultats avec la structure des matériaux. Il a été montré que le stade 2 dilué apparaît à LiC24. L’effet de la graphitisation sur l’intercalation du lithium a été considéré est clarifié. La phase hexagonale dans LixCoO2 s’étend sur un domaine plus large que précédement publié, allant jusqu’à x=0. 83. Les sources d’entropie possible ont été détaillées pour cette phase. L’effet de la sur-stoichiométrie dans LiMn2O4 a aussi été étudié. En résumé cette technique de mesure thermodynamique fournie de précieuses informations sur l’évolution structurale des matériaux d’électrode
Structural changes in lithium ion battery electrodes are a central issue to understand their electrochemical behavior. In this study a new system using the open circuit voltage evolution as a function of temperature was developed to measure the thermodynamics of lithium intercalation. X-ray diffractometry was also used to correlate the thermodynamic profiles to the structure. Clear results also showed that liquid like stage 2 appears at LiC24. The effect of the graphitization degree on lithium intercalation was also considered and clarified. The hexagonal phase in LixCoO2 was found to extend up to x~0. 83 instead of 0. 75 as previously thought. A detailed survey of the possible sources of entropy was carried out for this compound. The effect of over stoichiometry in LiMn2O4 was also studied. The open circuit voltage method can give valuable information on the structural evolution of electrode materials and is easy to setup, making it an interesting mean of structural characterization

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Takeno, Mitsuhiro. « Studies on Electrode-slurry for Lithium-ion Batteries ». Kyoto University, 2017. http://hdl.handle.net/2433/225964.

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Ng, See How. « Nanostructured materials for electrodes in lithium-ion batteries ». Access electronically, 2007. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20080313.142752/index.html.

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Wang, Shijun. « Iron phosphates as cathodes for lithium-ion batteries ». Diss., Online access via UMI:, 2009.

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Alotaibi, Nouf. « Rutile-TiO2 based materials for lithium ion batteries ». Thesis, University of Sheffield, 2015. http://etheses.whiterose.ac.uk/11130/.

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Although widely used, the most promising Li-based energy storage systems still suffer from a lack of suitable electrodes. There is therefore a need to seek new materials to satisfy the increasing demands for energy storage worldwide. TiO2 is a very promising anode material for lithium rechargeable batteries. It has a low insertion voltage of Li and high theoretical specific capacity. However, Li insertion into bulk rutile is negligible at room temperature due to the dense close packing of the rutile structure; also it suffers from a poor electronic conductivity. The electrochemical performance of pure rutile reveals that only 0.11 mol of Li can be inserted into rutile structure with a specific capacity of 26 mAh/ g. The main objective of this thesis has been to seek ways to improve the performance and charge storage capacity of rutile by compositional modification Improvement of the electronic conductivity of rutile by quenching oxygen-deficient samples and its influence on electrochemical performance have been studied and compared with that of fully oxidized rutile. An improvement in charge-discharge capacity was achieved; 0.21 Li per mol of TiO2 corresponding to 49 mAh/ g in the first cycle, but for subsequent cycles, both became similar which indicates that increasing the electronic conductivity by quenching did not give a long term improvement and suggests that lattice dimensions rather than electronic conductivity may be the reason for the poor perfomance of rutile anode. Substitution of Ti4+ with metal ions of either similar or different valence to increase the lattice dimensions and/or to increase the electronic conductivity is an option to improve the electrochemical performance of rutile TiO2. In this study, the effect of doping with large Sn4+ and co-doping with Cu-M (M= Nb, Ta) on the electrical and electrochemical performance is presented. The objective was first, to increase the unit cell dimensions of rutile by doping. This is based on the hypothesis that insertion of Li into TiO2 rutile would be easier with an expanded unit cell. Solid solutions have been prepared via solid state reaction where Ti4+ is partially replaced by either Sn4+ or a combination of divalent (Cu2+) and pentavalent ions (Nb5+, Ta5+). Single-phase solid solutions of the doped systems have been characterised by XRD and indexed on a tetragonal rutile structure; lattice parameter refinement confirms the expansion in the unit cell dimensions. Lithium test cells were fabricated using the rutile solid soultions as anodes. The first discharge step reveals that up to one mole of Li ion can intercalate into codoped Cu-Nb or Cu-Ta at room temperature with a discharge capacity up to 78 mAh/g while a specific capacity of 154 mAh/ g was delivered by Sn-doped rutile. These examples of lattice expanded doped rutile show a much higher electroactivity towards Li insertion than undoped rutile with excellent retention of capacity during cycling. Ex-situ XRD indicates excellent structural stability during cycling with no evidence of major changes in the rutile crystal structure. However, a major drawback in their electrochemical behaviour was a significant loss of capacity on cycling. The variation in the electrical properties of doped systems with the nature and composition of metal electrode and atmosphere was studied for Cu-Nb and Cu-Ta co-doped rutile. The formation of a potential barrier, due to the presence of residual phase at the grain boundary, was indicated by impedance spectroscopy (IS) in codoped system, the data showing a Schottky-like nature. The SnxTi1-xO2 system exhibits resistive behaviour, with high activation energy for all compositions. The effect of rutile TiO2 as starting material on the electrochemical performance of Li4Ti5O12 (LTO) was examined and compared with that of anatase TiO2. High purity LTO was obtained using rutile starting material but the specific capacity was slightly higher for LTO prepared using anatase than rutile.

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Amigues, Adrien Marie. « New metastable cathode materials for lithium-ion batteries ». Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/276299.

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This PhD work is dedicated to the discovery and study of new cathode materials for lithium-ion batteries. To obtain new materials, a well-known strategy based on ion-exchanging alkali metals within stable crystalline frameworks was used. Ion-exchange procedures between sodium and lithium ions were performed on known sodiated materials, NaMnTiO4 with the Na0.44MnO2 structure and NaFeTiO4 and Na2Fe3-xSn2xSb1-xO8 (0 ≤ x ≤ 1) with the calcium-ferrite structure. A combination of Energy-Dispersive X-ray Spectroscopy (EDS), Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), X-ray (XRD) and Neutron (NPD) diffractions was used to determine the crystal structure of the samples obtained via ion-exchange and confirmed that LiMnTiO4 and LiFeTiO4 and Li2Fe3-xSn2xSb1-xO8 (0 ≤ x ≤ 1) were obtained with a 1:1 ion-exchange between sodium and lithium. LiMnTiO4 has the orthorhombic Pbam space group, with a = 9.074(5), b = 24.97(1) and c = 2.899(2) Å. The shapes and dimensions of the channels are modified compared to NaMnTiO4, with displaced alkali metal positions and occupancies. LiMnTiO4 was cycled vs Li and up to 0.89 lithium ions can be reversibly inserted into the structure, with a discharge capacity of 137 mAh/g after 20 cycles at C/20 and room temperature. At 60°C, all the lithium is removed at the end of the first charge at C/20, with subsequent cycles showing reversible insertion of 1.06 Li-ions when cycled between 1.5 and 4.6 V. The electrochemistry of calcium-ferrite LiFeTiO4 and Li2Fe3SbO8 was investigated in half cells versus lithium and up to 0.63 and 1.35 lithium ions can be reversibly inserted into the structure after 50 cycles at a C/5 rate, respectively. LiFeTiO4 showed good cyclability with no capacity fade observed after the second cycle while Li2Fe3SbO8 exhibited a constant capacity fade with a 60 % capacity retention after the 50th cycle. Doping Li2Fe3SbO8 with tin reduces the capacity. However, the capacity retention is significantly enhanced. For Li2Fe2.5Sb0.5SnO8 after 20 cycles at C/5, the capacity is stable and comparable with that observed for Li2Fe3SbO8 after the same number of cycles. Using ion-exchange procedures has allowed new metastable materials to be obtained which have the potential to be used as cathodes in lithium-ion batteries. Doping these families of materials with different atoms has been shown to improve their electrochemical performance. Ex situ XRD was used to demonstrate that the original structures of LiMnTiO4, LiFeTiO4 and Li2Fe3SbO8 are retained during cycling. The volume change observed for Li2Fe3SbO8 upon delithiation was particularly noteworthy with a small decrease of 0.9 % at the end of charge when cycled at C/100 and room temperature, indicating structural stability upon lithium insertion/de-insertion.

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Allart, David. « Gestion et modélisation électrothermique des batteries lithium-ion ». Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC261/document.

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Ces travaux de thèse se focalisent sur la modélisation électrothermique des batteries Lithium-ion de grande puissance, appliquée pour les véhicules électriques et pour le stockage d’énergie intégré au réseau. Une approche plus particulière est donnée sur la modélisation thermique de la batterie et de ses connectiques dans le but d’anticiper les comportements thermiques sous des sollicitations dynamiques de courant. De nombreuses investigations ont été réalisées dans le but de déterminer les différents paramètres électriques et thermiques de l’accumulateur, nous avons également cherché à comparer plusieurs méthodes de caractérisation différentes.La première partie du manuscrit est consacrée à la caractérisation et à la modélisation électrique.La seconde partie présente la caractérisation thermique et le modèle thermique de la batterie. Nous proposons une approche couplée de différents modèles thermiques, dans le but de prédire les comportements thermiques au niveau de la surface et du cœur de la cellule, mais également au niveau des connectiques et des câbles.Enfin, la dernière partie présente la modélisation électrothermique d’un module assemblé de trois cellules en séries. Les résultats de simulations ont été validés sur des régimes à courant constant, ainsi que sur des régimes de courant dynamique.Le travail accompagne l’intégration des modèles thermiques dans une plateforme de simulation de systèmes énergétique et ouvre des pistes vers des outils d’aide à la conception de packs de batteries, sur l’aide au dimensionnement de systèmes de refroidissement et sur le développement d’outil de diagnostic thermique des batteries
This thesis work focuses on the electrothermal modeling of high-power Lithium-ion batteries, applied for electric vehicles and the energy storage connected to the the grid. A particular approach is given on the thermal modeling of the battery and its connectors in order to anticipate the thermal behaviors under dynamic charge and discharge current, which is very useful for the thermal management systems of the batteries. Numerous investigations have been carried out in order to determine the different electrical and thermal parameters of the accumulator, we have also tried to compare several different methods.The first part of the manuscript is dedicated to characterization and electrical modeling.The second part presents the thermal characterization and the thermal model of the battery. We propose a coupled approach of different thermal models, with the aim of predicting the thermal behaviors at the level of the surface and the core of the cell, but also at the level of the connectors and the wire.Finally, the last part presents the electrothermal modeling of a small assembled module of three cells in series. The results of simulations have been validated on constant current regimes, as well as on dynamic current regimes.The work aims to integrate the thermal models in a simulation platform of energy systems and opens up paths towards tools to help in the design of battery packs, assistance with the dimensioning of cooling systems and the development of thermal diagnostic tool for batteries

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ANDREOLI, ALFREDO. « Nano-structured Germanium anodes for Lithium-ion batteries ». Doctoral thesis, Università degli studi di Ferrara, 2021. http://hdl.handle.net/11392/2488288.

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Lithium-Ion Batteries represent the leading technology of the nowadays energy storage systems and are expected to play a fundamental role in the transition towards a green and sustainable economy. Nevertheless, the current commercial devices are close to meet their theoretical limits, thereby new materials with higher capacity, energy density and superior rate capability, are required. Among the various possibilities, germanium is regarded with particular interest to replace the actual standard for the negative electrode, which is graphite, as it shows a higher theoretical capacity and promising electrochemical properties that could make it suitable for fast charge and discharge applications. The major drawback hindering the direct exploitation of this material is represented by a huge volumetric expansion through the charge and discharge processes, leading to the pulverization of bulk materials within few cycles. A possible solution to overcome this issue is to nano-structure the semiconductor material down to a size in which it becomes compliant to the volumetric variations. In this thesis work, two processes to realize efficient and reliable germanium-based nano-structured anodes for high capacity and superior rate capability Lithium-Ion Batteries are presented, accompanied by a thoroughly physical and electrochemical characterization of the electrodes. The fabrication processes make use of standard techniques that are already widely employed in the industry of semiconductors that are not typically exploited by the battery industry. In this process a thin germanium film is realized first, by means of a Low Energy Plasma Enhanced Chemical Vapor Deposition and is subsequently nano-structured recurring to one out of two techniques, represented by Hydrofluoric acid Electrochemical Etching and Ion Implantation. The electrodes realized do not require any binder, conductive agent, or seed layer, that is important to enhance the overall gravimetric capacity of the cells as well as simplifying the fabrication process. The details of the fabrication process, as well as a review of the experimental results in comparison with previous works, theoretical models, and the literature, are presented. The extensive physical and electrochemical characterizations of the electrodes are deepened in specific chapters, where brief introductions of the techniques and methods used are also reported. The electrodes show very high capacities, well above that of graphite, which are retained for hundreds or even thousands of cycles. Remarkable retention at elevated rates is also observed, as well as a promising performance in a wide temperature range (-30 °C ÷ 60 °C). These interesting results are demonstrated to be completely ascribed to the nano-structured germanium, irrespective of the substrate materials, the nano-structuration technique, or the cell testing procedure used. The nano-structured germanium anodes presented in this work are particularly appealing for aerospace applications, where highly reliable materials are required. Part of the activities here presented were carried out in the framework of a project financed by the Italian Space Agency and named “ANGELS”. The promising results observed since the first prototypes, led also to the filing of a patent family (original application IT201800006103A) on the fabrication process consisting in the deposition and the subsequent electrochemical dissolution.
Le Batterie agli Ioni di Litio sono la tecnologia di punta tra i sistemi di accumulo dell’energia attuali e ci si aspetta che giocheranno un ruolo fondamentale nella transizione verso una economia verde e sostenibile. Tuttavia, la tecnologia odierna è vicina al raggiungimento dei propri limiti teorici e sono pertanto richiesti nuovi materiali con densità energetica superiore e una migliore risposta ad elevati ratei di carica e scarica. Tra le varie possibilità, il germanio è particolarmente interessante per rimpiazzare il materiale attualmente utilizzato come standard negli anodi delle batterie, rappresentato dalla grafite. Il germanio ha infatti una capacità teorica superiore e promettenti performance elettrochimiche lo renderebbero particolarmente adatto per applicazioni di potenza. Il principale limite che ne impedisce lo sfruttamento diretto è rappresentato da una forte variazione volumetrica durante i cicli di carica e scarica, che porta alla polverizzazione del materiale massiccio nell’arco di pochi cicli. Una possibile soluzione per risolvere questo problema consiste nella nano-strutturazione del materiale, per creare strutture in grado di accomodare reversibilmente le deformazioni. In questo lavoro di tesi si presentano due processi articolati in due fasi per la realizzazione di anodi nano-strutturati a base di germanio con capacità superiori e migliori performance ad elevati ratei di carica e scarica, presentando anche una approfondita campagna di caratterizzazioni fisiche ed elettrochimiche dei campioni realizzati. I processi di fabbricazione in due fasi fanno ricorso a tecniche che rappresentano già degli standard nell’industria dei semiconduttori, ma che non sono ancora diffusi in quella delle batterie. In particolare, si tratta di approcci “top-down” nei quali si realizza in primis un film sottile di germanio ricorrendo a una deposizione chimica da fase vapore assistita da un plasma a bassa energia, per poi realizzare la nano-struttura ricorrendo a una delle due tecniche tra l’attacco elettrochimico con acido fluoridrico o l’impiantazione ionica. Gli elettrodi così prodotti non necessitano di additivi per incrementare l’adesione o la conducibilità, e non occorrono deposizioni preliminari per assisterne la crescita: questi costituiscono aspetti importanti per incrementare la capacità per unità di massa degli elettrodi oltre a semplificare i processi di fabbricazione. I dettagli dei processi di realizzazione degli elettrodi e una rassegna dei risultati sperimentali sono illustrati e confrontati con precedenti lavori, con modelli teorici e con la letteratura. Le caratterizzazioni fisiche ed elettrochimiche effettuate sono presentate in appositi capitoli, fornendo brevi introduzioni delle tecniche e delle metodologie di analisi utilizzate. Gli elettrodi hanno dimostrato ottime capacità, superiori alla grafite, che vengono mantenute per centinaia o migliaia di cicli. L’elevata capacità degli elettrodi è mantenuta anche ad elevati ratei di carica e scarica ed in un ampio range di temperature. Inoltre, si dimostra che i promettenti risultati osservati sono ascrivibili esclusivamente al germanio nano-strutturato, e sono indipendenti dal materiale substrato, dalla tecnica di nano-strutturazione usata e dal particolare test elettrochimico effettuato. Gli anodi presentati in questo lavoro risultano particolarmente promettenti per applicazioni aerospaziali. Parte delle attività presentate è stata svolta nell’ambito di un progetto finanziato dall’Agenzia Spaziale Italiana e denominato ANGELS. In virtù dei risultati ottenuti sin dai primi prototipi, il processo di realizzazione degli anodi tramite la deposizione e la successiva nano-strutturazione mediante dissoluzione anodica è stato protetto da una famiglia di brevetti, con capostipite il brevetto italiano IT201800006103A.

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Jeschull, Fabian. « Functional Binders at the Interface of Negative and Positive Electrodes in Lithium Batteries ». Licentiate thesis, Uppsala universitet, Strukturkemi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-267557.

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In this thesis, electrode binders as vital components in the fabrication of composite electrodes for lithium-ion (LIB) and lithium-sulfur batteries (LiSB) have been investigated. Poly(vinylidene difluoride) (PVdF) was studied as binder for sulfur-carbon positive electrodes by a combination of galvanostatic cycling and nitrogen absorption. Poor binder swelling in the electrolyte and pore blocking in the porous carbon were identified as origins of low discharge capacity, rendering PVdF-based binders an unsuitable choice for LiSBs. More promising candidates are blends of poly(ethylene oxide) (PEO) and poly(N-vinylpyrrolidone) (PVP). It was found that these polymers interact with soluble lithium polysulfide intermediates generated during the cell reaction. They can increase the discharge capacity, while simultaneously improving the capacity retention and reducing the self-discharge of the LiSB. In conclusion, these binders improve the local electrolyte environment at the electrode interface. Graphite electrodes for LIBs are rendered considerably more stable in ‘aggressive’ electrolytes (a propylene carbonate rich formulation and an ether-based electrolyte) with the poorly swellable binders poly(sodium acrylate) (PAA-Na) and carboxymethyl cellulose sodium salt (CMC-Na). The higher interfacial impedance seen for the conventional PVdF binder suggests a protective polymer layer on the particles. By reducing the binder content, it was found that PAA-Na has a stronger affinity towards electrode components with high surface areas, which is attributed to a flexible polymer backbone and a higher density of functional groups. Lastly, a graphite electrode was combined with a sulfur electrode to yield a balanced graphite-sulfur cell. Due to a more stable electrode-electrolyte interface the self-discharge of this cell could be reduced and the cycle life was extended significantly. This example demonstrates the possible benefits of replacing the lithium metal negative electrode with an alternative electrode material.

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Ali, Haider Adel Ali, et Ziad Namir Abdeljawad. « THERMAL MANAGEMENT TECHNOLOGIES OF LITHIUM-ION BATTERIES APPLIED FOR STATIONARY ENERGY STORAGE SYSTEMS : Investigation on the thermal behavior of Lithium-ion batteries ». Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-48904.

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Batteries are promising sources of green and sustainable energy that have been widely used in various applications. Lithium-ion batteries (LIBs) have an important role in the energy storage sector due to its high specific energy and energy density relative to other rechargeable batteries. The main challenges for keeping the LIBs to work under safe conditions, and at high performance are strongly related to the battery thermal management. In this study, a critical literature review is first carried out to present the technology development status of the battery thermal management system (BTMS) based on air and liquid cooling for the application of battery energy storage systems (BESS). It was found that more attention has paid to the BTMS for electrical vehicle (EV) applications than for stationary BESS. Even though the active forced air cooling is the most commonly used method for stationary BESS, limited technical information is available. Liquid cooling has widely been used in EV applications with different system configurations and cooling patterns; nevertheless, the application for BESS is hard to find in literature.To ensure and analyze the performance of air and liquid cooling system, a battery and thermal model developed to be used for modeling of BTMS. The models are based on the car company BMW EV battery pack, which using Nickel Manganese Cobalt Oxide (NMC) prismatic lithium-ion cell. Both air and liquid cooling have been studied to evaluate the thermal performance of LIBs under the two cooling systems.According to the result, the air and liquid cooling are capable of maintaining BESS under safe operation conditions, but with considering some limits. The air-cooling is more suitable for low surrounding temperature or at low charging/discharge rate (C-rate), while liquid cooling enables BESS to operate at higher C-rates and higher surrounding temperatures. However, the requirement on the maximum temperature difference within a cell will limits the application of liquid cooling in some discharge cases at high C-rate. Finally, this work suggests that specific attention should be paid to the pack design. The design of the BMW pack is compact, which makes the air-cooling performance less efficient because of the air circulation inside the pack is low and liquid cooling is more suitable for this type of compact battery pack.

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Zou, Haiyang. « Development of a Recycling Process for Li-Ion Batteries ». Digital WPI, 2012. https://digitalcommons.wpi.edu/etd-theses/260.

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The rechargeable secondary Lithium ion (Li-ion) battery is expected to grow to more than $6.3 billion by 2012 from ~$4.6 billion in 2006. With the development of personnel electronics, hybrid and electric vehicles, Li-ion batteries will be more in demand. However, Li-ion batteries are not widely recycled because it is not economically justifiable (in contrast, at present more than 97% Lead-acid batteries are recycled). So far, no commercial methods are available to recycle different chemical Li-ion batteries economically and efficiently. Considering our limited resources, environmental impact, and national security, Li-ion batteries must be recycled. A new methodology with low temperature and high efficiency is proposed in order to recycle Li-ion batteries economically and with industrial viability. The separation and synthesis of cathode materials (most valuable in Li-ion batteries) from recycled components are the main focus of the proposed research. The analytical results showed that the recycling process is practical and has high recovery efficiency, create great commercial value as well.

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Santos-Ortiz, Reinaldo. « Thin Films As a Platform for Understanding the Conversion Mechanism of FeF2 Cathodes in Lithium-Ion Microbatteries ». Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc804977/.

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Conversion material electrodes such as FeF2 possess the potential to deliver transformative improvements in lithium ion battery performance because they permit a reversible change of more than one Li-ion per 3d metal cation. They outperform current state of the art intercalation cathodes such as LiCoO2, which have volumetric and gravimetric energy densities that are intrinsically limited by single electron transfer. Current studies focus on composite electrodes that are formed by mixing with carbon (FeF2-C), wherein the carbon is expected to act as a binder to support the matrix and facilitate electronic conduction. These binders complicate the understanding of the electrode-electrolyte interface (SEI) passivation layer growth, of Li agglomeration, of ion and electron transport, and of the basic phase transformation processes under electrochemical cycling. This research uses thin-films as a model platform for obtaining basic understanding to the structural and chemical foundations of the phase conversion processes. Thin film cathodes are free of the binders used in nanocomposite structures and may potentially provide direct basic insight to the evolution of the SEI passivation layer, electron and ion transport, and the electrochemical behavior of true complex phases. The present work consisted of three main tasks (1) Development of optimized processes to deposit FeF2 and LiPON thin-films with the required phase purity and microstructure; (2) Understanding their electron and ion transport properties and; (3) Obtaining insight to the correlation between structure and capacity in thin-film microbatteries with FeF2 thin-film cathode and LiPON thin-film solid electrolyte. Optimized pulsed laser deposition (PLD) growth produced polycrystalline FeF2 films with excellent phase purity and P42/mnm crystallographic symmetry. A schematic band diagram was deduced using a combination of UPS, XPS and UV-Vis spectroscopies. Room temperature Hall measurements reveal that as-deposited FeF2 is n-type with an electron mobility of 0.33 cm2/V.s and a resistivity was 0.255 Ω.cm. The LiPON films were deposited by reactive sputtering in nitrogen, and the results indicate that the ionic conductivity is dependent on the amount of nitrogen incorporated into the film during processing. The highest ionic conductivity obtained was 1.431.9E-6 Scm-1 and corresponded to a chemical composition of Li1.9PO3.3N.21. FeF2/LiPON thin films microbatteries were assembled using a 2032 coin cell configuration and subjected to Galvanostatic cycling. HRTEM and EELS spectroscopy where performed across the FeF2/LiPON interface of samples cycled once 15 times in their lithiated and delithiated states to understand the relationship between microstructural evolution and capacity. The EELS measurements provided evidence of a three-phase conversion reaction over the first discharge described by FeF2 +2e-+2Li+↔Fe +LiF, and of incomplete reconversion back to FeF2 after the 1st cycle resulting in new Fe0 and LiF phases in delithiated samples. This incomplete conversion results in (a) a smaller phase fraction of FeF2 participating in the conversion process subsequently and (b) the formation of LiF which is resistive to both electron and ion transport. This results in the observed drastic drop in capacity after the1st cycle. More study to understand the reconversion reaction pathways is required to fully exploit the potential of FeF2 and other conversion materials as cathodes in Li ion batteries.

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